Phenolic compounds in the freshwater environment in South Korea: Occurrence and tissue-specific distribution

In this study, we investigated the occurrence and distribution of phenolic compounds, including phenol, cresols, chlorophenols, nitrophenol, and bromophenols, in freshwater environments. We also focused on phenolic compounds in crucian carp (Carassius auratus) tissues, specifically the muscle, gills, brain, blood, liver, and gonads, to assess their potential bioaccumulation in fish and human health risks. Phenolic compounds were found to be widespread in various freshwater environments throughout South Korea. Phenol was predominant in all matrices, with median concentrations of 57.0 ng/L in freshwater, 54.3 ng/g dry weight (dw) in sediment, and ranging from 71 ng/g wet weight (ww) to 621 ng/g ww in crucian carp tissues. Cresols were the second most dominant compound, with m-cresol exhibiting the highest prevalence. Most of the compounds detected in crucian carp samples were also detected in freshwater and sediment, whereas pentachlorophenol and 2,4,6-tribromophenol were exclusively detected in crucian carp tissues. A high bioaccumulation potential in the liver was observed for most phenolic compounds [median log bioconcentration factor (BCF): 3.2-3.7]. Interestingly, only m-cresol showed high bioaccumulation potential in the gills (median log BCF: 3.1). The estimated daily intake of phenolic compounds suggested that it does not pose an immediate concern for human exposure owing to crucian carp consumption. These findings enhance our understanding of the exposure status, distribution, and bioaccumulation potency of phenolic compounds in aquatic ecosystems and emphasize the importance of ongoing monitoring and risk assessment efforts.